Multiheteromacrocycles will be designed and synthesized as host molecules for molecular complexation of guest molecules such as amino acids, primary amines, aryldiazonium salts, and the alkali and alkaline earth metal salts. Systems will be developed that allow the degree of complexation and selectivity between host and guest to be examined. Some of the host molecules will contain rigid chiral barriers for use in enantiomer differentiation in molecular complexation. Some host molecules will contain side chains that contain counterions or additional binding and shaping sites.